Shelf system



FIG. 1 is a side elevational view of the shelf system embodying my new design, and shown with the shelves in an open position;

FIG. 2 is a front view thereof;

FIG. 3 is a perspective view thereof, showing a detachable shelf portion and showing one shelf in an open position; and,

FIG. 4 is perspective view thereof showing shelf portions in a closed position. 

The ornamental design for a shelf system, as shown and described. 